The present invention relates to a DNA which codes for a polypeptide with interferon activity and a recombinant plasmid containing the DNA. The present invention also pertains to a microorganism containing the recombinant plasmid.
Interferon is a glycoprotein (molecular weight approx. 20,000) with antiviral activity, discovered by Isaacs and Lindenmann in 1957. Subsequent studies have indicated antitumor activity of the substance in addition to antiviral activity and hence a wide clinical application of this substance is expected. For instance, it has been reported that interferon may be effectively administered to various viral diseases, osteosarcoma and mammary carcinoma.
However, because of its high species-specificity, only the interferon derived from human cells can be used for human application. At present, the interferon which is being used for administration has a relative activity of about 10.sup.6 (International units) per 1 mg, which corresponds to a purity of about 0.1-0.01%.
Moreover, the use of the interferon is quite limited because of difficulties in mass-production. At present even for the interferon requirement for clinical tests (10.sup.13 units per year), the supply is only about 1%. For these reasons, development of technology to produce human interferon in high purity, with ease and in large quantities is in demand.
To this end, a novel technique has been developed for producing interferon with ease and in a large quantity by inserting a human interferon gene into a plasmid DNA (for instance plasmid DNA derived from Escherichia coli) with recombinant DNA (deoxyribonucleic acid) technology.